In FIG. 1, a conventional fuel injection device from the related art is shown as an example, in which a flat intermediate element is provided on a fuel injector installed in a receiving borehole of a cylinder head of an internal combustion engine. Such intermediate elements are placed in a conventional way as support elements in the form of a washer on a shoulder of the receiving borehole of the cylinder head. With the aid of such intermediate elements, manufacturing and assembly tolerances are compensated and a mounting free of lateral forces is ensured even at a slight inclination of the fuel injector. The fuel injection device is suited in particular for use in fuel injection systems of mixture-compressing spark-ignition internal combustion engines.
Another type of a simple intermediate element for a fuel injection device is described in German Patent Application No. DE 101 08 466 A1. The intermediate element is a washer having a circular cross section which is situated in an area, in which both the fuel injector and the wall of the receiving borehole are truncated in the cylinder head, and is used as a compensating element for mounting and supporting the fuel injector.
More complex, and significantly more expensive to manufacture intermediate elements for fuel injection devices are described in German Patent Application Nos. DE 100 27 662 A1 and DE 100 38 763 A1, and European Patent Application No. EP 1 223 337 A1, among others. These intermediate elements are characterized in that they all have a multipart or multilayered design, and are to take on sealing and damping functions in part.
The intermediate element described in German Patent Application No. DE 100 27 662 A1 includes a base- and support body, in which a sealing element is inserted which is penetrated by a nozzle body of the fuel injector. In German Patent Application No. DE 100 38 763 A1, a multilayer compensating element is known, which is composed of two rigid rings and an elastic intermediate ring situated sandwiched therebetween. This compensating element enables both a tilting of the fuel injector toward the axis of the receiving borehole across a relatively large angle range and a radial displacement of the fuel injector from the center axis of the receiving borehole.
A likewise multilayered intermediate element is also described in European Patent Application No. EP 1 223 337 A1, this intermediate element being composed of multiple washers which are made of a muffling material. The muffling material, made from metal, rubber, or PTFE, is selected and designed in such a way that noise muffling of the vibrations and noises generated by operating the fuel injector is enabled. The intermediate element must, however, include four to six layers for this purpose to achieve a desired muffling effect.
For reducing noise emissions, U.S. Pat. No. 6,009,856 A moreover proposes to surround the fuel injector with a sleeve and to fill the resulting intermediate space with an elastic, noise-muffling material. This type of noise muffling is, however, very complex, installation unfriendly, and expensive.